1. Field of the Invention
The present invention relates to a multihole socket of a power extension cord, and particularly, to a flexible socket of a power source hub for a power extension cord, in which the sockets can be easily displaced so as to facilitate the plug-in of plugs of electrical appliances.
2. Description of the Related Art
Nowadays, the number of household electrical appliances becomes more and more, and the number of sockets for use is often limited. In particular, a great number of sockets are needed for a computer and its peripherals. In general, a power extension cord having a plurality of multihole sockets is used to fulfill the need. However, such a power extension cord is defective in that when, for example, an adapter or a battery charger is plugged in one of the sockets, its neighboring sockets cannot be used as the holes of the sockets are often blocked or covered by a portion of the adapter or battery charger. It may be convenient to use the power extension cord, but hazardous situations might happen if care is not taken during the use. In particular, the sockets of the extension cord with small wire diameter are almost unable to cope with high-power consumption appliances and the full load thereof. Users are always subject to potential danger.
In order to overcome the disadvantage of the sockets of the conventional extension cord, for example, as shown in FIGS. 1 and 2, the Applicant, in Taiwan patent publication No. 200744267 (corresponding to US patent publication No. 2007/0273298 A1) proposed a multihole socket of a power extension cord, wherein the sockets may be moved with respect to each other due to the flexible cables of the sockets. Although the invention as disclosed in the above-mentioned patent publication may provide improvement over the conventional power extension cord, it is found that it is not easy to bend the flexible cable to displace during use. Particularly, the cable with strands having a wire diameter of over 1.10 mm2 has a comparatively high rigidity, and it is not easy to temporarily displace the sockets. As shown in the cross sectional view of FIG. 2, each socket mainly comprises a cable formed of three strands. In a free state, the three strands of the cable are substantially formed in a triangular arrangement, and the outer layer thereof is wrapped with a P.V.C. material. Therefore, whichever direction the cable is bent, an interference will exist between the three-strands cable and the wrapping material. In terms of physical property, the radius of curvature at the inside part of the bent cable and wrapping material is small, and the radius of curvature at the outside part of the bent cable and wrapping material is large. In a state that the cable and wrapping material are not expandable in whichever directions, it is, of course, difficult to bend. There is still a room for improvement in this respect.